CN101395660A - Audio decoding techniques for mid-side stereo - Google Patents

Audio decoding techniques for mid-side stereo Download PDF

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Publication number
CN101395660A
CN101395660A CNA2007800070939A CN200780007093A CN101395660A CN 101395660 A CN101395660 A CN 101395660A CN A2007800070939 A CNA2007800070939 A CN A2007800070939A CN 200780007093 A CN200780007093 A CN 200780007093A CN 101395660 A CN101395660 A CN 101395660A
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sound channel
decoding
audio
imdct
information
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萨蒂亚纳拉亚纳·卡卡拉
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Qualcomm Inc
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
    • G10L19/00—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
    • G10L19/008—Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M7/00—Conversion of a code where information is represented by a given sequence or number of digits to a code where the same, similar or subset of information is represented by a different sequence or number of digits
    • H03M7/30—Compression; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
    • H03M7/40—Conversion to or from variable length codes, e.g. Shannon-Fano code, Huffman code, Morse code
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S1/00—Two-channel systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2499/00—Aspects covered by H04R or H04S not otherwise provided for in their subgroups
    • H04R2499/10—General applications
    • H04R2499/11—Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S2420/00—Techniques used stereophonic systems covered by H04S but not provided for in its groups
    • H04S2420/03—Application of parametric coding in stereophonic audio systems

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Signal Processing (AREA)
  • Acoustics & Sound (AREA)
  • Audiology, Speech & Language Pathology (AREA)
  • Health & Medical Sciences (AREA)
  • Computational Linguistics (AREA)
  • Human Computer Interaction (AREA)
  • Mathematical Physics (AREA)
  • Multimedia (AREA)
  • Theoretical Computer Science (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)
  • Stereophonic System (AREA)

Abstract

This disclosure describes decoding techniques for audio information encoded according to mid-side (MS) stereo encoding. The techniques involve a number of audio decoding tasks that are performed in a non-conventional order. By rearranging the order of the decoding tasks, various efficiencies can be achieved. In one embodiment, a method of decoding MS stereo audio information includes decoding a first channel of the audio information, computing an inverse modified discrete cosign transform (IMDCT) for the first channel prior to generating MS stereo information, decoding the second channel of the audio information, computing an IMDCT for the second channel prior to generating the MS stereo information, and generating the MS stereo information using the IMDCTs for the first and second channels.

Description

Be used for the stereosonic audio decoder technology of side
Technical field
The present invention relates to the audio coding technology, and more particularly, relate to the decoding technique that is used for the audio-frequency information of encoding according to side (MS) stereo coding technology.
Background technology
Audio coding is used for many application and environment, and for example satelline radio, digital radio, the Internet flows (web radio), digital music player and various mobile multimedia are used.There are many audio coding standard, for example according to the standard of moving image expert group (MPEG), Windows media audio (windows media audio) (WMA) with according to incorporated company of Dolby Labs (Dolby Laboratories, standard Inc).Many audio coding standard continue to occur, and comprise the succession of MP3 standard and MP3 standard, for example in Apple computer incorporated company (Apple Computer, Advanced Audio Coding (AAC) standard of using in " iPod " that Inc) the sells device.Audio coding standard seeks to use compress technique to reach low bit rate, high quality audio coding usually.Some audio coding is " can't harm ", and it means the described coding sound signal of not demoting, and other audio coding can be introduced some loss to reach extra compression.
In many application, audio coding makes with the video coding and is used for providing content of multimedia for using (for example visual telephone (VT) or stream-type video).For example, often use the Voice ﹠ Video coding according to the video encoding standard of MPEG.Current, described mpeg standard comprises MPEG-1, MPEG-2 and MPEG-4, but other standard may occur.Other exemplary video standards comprise International Telecommunication Union H.263 standard, ITU H.264 standard, by the QuickTime of Apple computer incorporated company exploitation TMTechnology, by Microsoft (MicrosoftCorporation) exploitation at Windows TMVideo, by the Indeo of Intel company (Intel Corporation) exploitation TM, from Rui Naiwo incorporated company (RealNetworks, RealVideo Inc) TMWith by Xiu Maike incorporated company (SuperMac, Inc) Kai Fa Cinepak TMSome Voice ﹠ Video standard is open source, and other still is proprietary.Many other Voice ﹠ Video coding standards can continue to occur and evolution.
Stereo coding is meant the audio coding that uses two different coding sound channels.Because human have two ears that can oriented approach detect sound, so stereo coding can be improved human from the quality through the detected institute of decoded audio signal perceived sounds.One relatively intuitively the mode of encoded stereo acoustic information be to use a left side and R channel encode respectively a left side and right signal.Yet for the complex sound of for example music disc, because a left side and right microphone can detect the fact of the same sound that is in the different time delay, a left side and right coding sound channel are not handy especially.For this reason, developed the stereo stereo sound quality that improves of middle side (MS).
In MS is stereo, use two unlike signals encode the respectively position of sound source and the reverberation environment of stereo image.Basically, stereo via M signal and the avris signal MS that encodes.After the decoding, L channel normally two encoded sound channels and, and normally described two the encoded sound channels of R channel is poor.By using middle stereo component and side stereo component, can utilize the stereo redundancy in a left side and the R channel to reach the more stereo coding of good quality, and at the better compression level of set quality level.
Summary of the invention
The present invention describes the decoding technique be used for the audio-frequency information of encoding according to side (MS) stereo coding.Described technology relates to many audio decoder tasks of carrying out with unconventional order.By rearranging the order of described decoding task, can realize various efficient.For example, can first sound channel be revised inverse discrete cosine transform (IMDCT) calculation task and second sound channel be carried out the pre decoding tasks in parallel and carry out and eliminate or reduce stand-by period in the decode procedure by allowing.Specific, when exchanging (DME) when technology is used with direct memory, described technology can allow from memory fetches employed decoding table (for example, Huffman (Huffman) table) when another sound channel being carried out load sound channel of decoding concurrently when IMDCT calculates.In this way, described technology provides the advantage in the calculating and can quicken the audio decoder process.
In one embodiment, the invention provides a kind of device, it comprises the storer of storing encoded audio-frequency information and the decoder element of decoding described information.Decode first sound channel of described audio-frequency information of described decoder element, before producing the MS stereo information, calculate the IMDCT of first sound channel, decode second sound channel of described audio-frequency information, before producing described MS stereo information, calculate the IMDCT of second sound channel and use described first and the IMDCT of described second sound channel produce the MS stereo information.
In another embodiment, the invention provides a kind of method of the MS of decoding stereo audio information.Described method comprises first sound channel of the described audio-frequency information of decoding, before producing the MS stereo information, calculate the IMDCT of first sound channel, decode second sound channel of described audio-frequency information, before producing described MS stereo information, calculate the IMDCT of second sound channel and use the IMDCT of described first and second sound channels to produce described MS stereo information.For utilizing this technology, can the IMDCT computing interval of described first sound channel carry out load the decoding table that is used for described second sound channel from memory fetches.
Can be in hardware, software, firmware or its arbitrary combination with these and other technology implementation described herein.If be implemented in the software, can in the processor of digital signal processor (DSP) or other type, carry out described software so.The software of carrying out described technology can initially be stored in the computer-readable media and load and be executed among the DSP with audio decoder effectively according to the stereo coded audio-frequency information of MS.
Therefore, the present invention also considers to comprise the computer-readable media of executable instruction, first sound channel of meeting decoded audio information when described executable instruction is carried out in supporting the stereosonic device of MS, before producing the MS stereo information, calculate the IMDCT of described first sound channel, decode second sound channel of described audio-frequency information, before producing described MS stereo information, calculate the IMDCT of described second sound channel and use the IMDCT of described first and second sound channels to produce described MS stereo information.
In another embodiment again, the invention provides the decoder element that is used for audio decoding apparatus, first sound channel of wherein said decoder element decoded audio information, before producing the MS stereo information, calculate the conversion of described first sound channel, decode second sound channel of described audio-frequency information, before producing described MS stereo information, calculate the conversion of described second sound channel and use the conversion of described first and second sound channels to produce described MS stereo information.
At accompanying drawing with hereinafter set forth the additional detail of each embodiment in the explanation.To understand other features, objects and advantages from this explanation and graphic and accessory rights claim.
Description of drawings
Fig. 1 is the block scheme that can implement the example audio decoding apparatus of technology of the present invention.
Fig. 2-the 4th, the process flow diagram of the technology that graphic extension can be carried out by the audio decoding apparatus of Fig. 1 or other similar device.
Embodiment
The present invention describes the decoding technique be used for the audio-frequency information of encoding according to side (MS) stereo coding.In MS is stereo, use two different signals encode the respectively position of sound source and the reverberation environment of stereo image.Basically, stereo from middle signal and the avris signal MS that encodes.After decoding MS is stereo, L channel normally the first and second encoded sound channels and, and the normally described first and second encoded sound channels of R channel is poor.Also can put upside down a left side and R channel.
Conventional MS stereo decoding relates to the re-quantization of the described sound channel of decoding heel of sound channel 1.Next, the re-quantization of the described sound channel of decoded channels 2 heels.Then, from calculate the stereo information of a left side and R channel through the sound channel 1 and 2 of decoding.For example, L channel MS stereo information can comprise sound channel 1+ sound channel 2, and R channel MS stereo information can comprise sound channel 1-sound channel 2.Next, be relevant to the L channel stereo information and carry out correction inverse discrete cosine transform (IMDCT), carry out windowing and reproduce the audio samples that is used for L channel.Similarly, be relevant to the R channel stereo information and carry out IMDCT, carry out windowing and reproduce the audio samples that is used for R channel.In this way, conventional MS stereo decoding normally wherein IMDCT follow the order process of the generation of MS stereo information.
Technology described in the present invention can comprise the step that is similar to conventional MS stereo decoding, but carries out described step with unconventional order.Specifically, according to the present invention, before the MS stereo information that produces a left side and R channel, be relevant to sound channel 1 and 2 and carry out IMDCT.By rearranging the order of described decoding task, can realize various efficient.For example, can first sound channel be carried out the IMDCT calculation task and second sound channel be carried out pre decoding tasks in parallel ground and carry out and eliminate or reduce stand-by period in the decode procedure by allowing.Specific, when in digital signal processor (DSP) with direct memory exchange (DEM) when technology is used, described technology can allow from storer take in the data of the decoding table of a sound channel with another sound channel is carried out IMDCT and calculates executed in parallel.In this way, described herein technology can provide the advantage in the calculating and can quicken the audio decoder process.
The DME technology typically refer to that DSP carries out from memory fetches, it handles executed in parallel with DSP during the clock period of DSP.Also can use the storer or the treatment technology of other type, especially be supported in arbitrary technology of carrying out the ability that the parallel storage in the processor position loads on the chip during the calculation task of processor.
Fig. 1 is the block scheme that can implement the audio decoding apparatus 10 of technology of the present invention.Shown device 10 comprises storer 12 and MS stereo decoding unit 14.Storer 12 can be stored the audio-frequency information according to the MS stereo coding.Audio-frequency information may be receives by communication channel, for example for real-time audio, or may be stored in the storer 12 one section through time expand.Decoding unit 14 is carried out one or more technology of the present invention, to improve the decode procedure of audio-frequency information.Specific, first sound channel of decoding unit 14 decoded audio information, before producing the MS stereo information, calculate the IMDCT of first sound channel, decode second sound channel of described audio-frequency information, before producing described MS stereo information, calculate the IMDCT of second sound channel and use the IMDCT of described first and second sound channels to produce described MS stereo information.Then, the MS stereo information can be used to produce the signal that can drive a left side and right loudspeaker 16A and 16B.Specific, driving circuit 15 can receive and produce the driving voltage that is used for loudspeaker 16A and 16B from the MS stereo information of MS stereo decoding unit 14 and based on described MS stereo information.Driving circuit 15 can comprise one or more digital analog converters (DAC), power amplifier and other simulating signal adjusting part.
Two the encoded sound channels and the fact that produces the MS stereo information because conventional MS decoding need be decoded before carrying out IMDCT, so " bottleneck " can take place in the MS decoding.Yet,, can before the MS stereo information that produces a left side and R channel, carry out the IMDCT of each encoded sound channel (sound channel 1 and 2) according to the present invention.Observed IMDCT linear characteristic makes this variation become possibility.
In addition, by rearranging the step of decode procedure, can utilize parallel processing to reach efficient.For example, can be by allowing the decoding unit 14 and the pre decoding tasks in parallel ground of second sound channel that first sound channel execution IMDCT is eliminated or reducing stand-by period in the decode procedure.Specific, when the computing interval with the DME technology or support that when the similar techniques of memory fetches was used, described technology can allow decoding unit 14 and IMDCT to calculate the memory fetches of carrying out concurrently from storer 12.Can be carried in the decoding table (for example huffman table) that uses sound channel of decoding from memory fetches.Simultaneously, can carry out IMDCT at other sound channel calculates.In this way, decoding unit 14 can be reached the efficient in the calculating and can quicken the audio decoder process.
Device 10 any one that can comprise in numerous devices that can comprise the audio decoder ability.Example comprises for example direct broadcast system of digital music player, Digital Television, numeral, radio communication device, PDA(Personal Digital Assistant), laptop computer, desk-top computer, digital camera, digital recorder, honeycomb fashion or satelline radio phone, direct and two-way communicator (being called " intercom " sometimes) and the similar device of iPod.
Fig. 2 is the process flow diagram of the decode procedure that can be implemented by decoding unit 14 of graphic extension.Shown in first sound channel (21) of decoding unit 14 decoded audio information, and producing the IMDCT (22) that MS stereo information (25) calculates first sound channel before then.Next, second sound channel (23) of the described audio-frequency information of decoding unit 14 decodings, and producing the IMDCT (24) that MS stereo information (25) calculates described second sound channel before.
The calculating of the IMDCT of first and second sound channels can be followed following equation 1 and 2 haply:
L _ channel _ time _ output ′ = 2 N × Σ k = 0 N 2 - 1 L [ k ] cos ( 2 π N ( n + n 0 ) ( k + 1 2 ) ) ( Equation 1 )
R _ channel _ time _ output ′ = 2 N × Σ k = 0 N 2 - 1 R [ k ] cos ( 2 π N ( n + n 0 ) ( k + 1 2 ) ) ( Equation 2 )
Wherein L_ sound channel _ time _ output ' expression sound channel 1 IMDCT,
R_ sound channel _ time _ output ' expression sound channel 2 IMDCT,
L and R represent a left side and R channel spectral coefficient respectively,
N represents the audio frame length in the decoder element 14,
K represents the spectral coefficient frequency index,
N express time index, and
n 0Be constant.
Yet in other embodiments, decoder element 14 may use the conversion of other type but not IMDCT.
As illustrated in Fig. 2, decoding unit uses the IMDCT of first and second sound channels to produce MS stereo information (25).The MS stereo information comprises a left side and the right channel information that can be used to produce audio samples, and described audio samples can be used to define the drive signal that is used for a left side and right loudspeaker 16A and 16B again.In addition, left channel information can be the additivity combination from the IMDCT of sound channel 1 and 2, and right channel information can be the subtractive combination of the IMDCT of sound channel 1 and 2.Yet, can put upside down and define right and L channel and make up and R channel is the subtractive combination of IMDCT so that L channel is the additivity of IMDCT.The IMDCT that is created in that it should be noted that the MS stereo information calculates generation afterwards.
In most of the cases, decoding unit 14 also can be carried out re-quantization to first and second sound channels.Specifically, decoding unit 14 can be carried out re-quantization to described first sound channel before the IMDCT of first sound channel of calculating audio-frequency information, and can carry out re-quantization to described second sound channel before the IMDCT of second sound channel of calculating audio-frequency information.
In some cases, first and second sound channels of decoding can comprise Hofmann decoding or use other class likelihood decoder of look-up table.In the case, look-up table (for example, huffman table) can be loaded into the decoding unit 14 being used for each of encoded sound channel from storer 12, and may reload to be used for successive audio frames.Regrettably, huffman table can be relatively large, especially decoding unit 14 be embodied as do not comprise than large chip on during the DSP of storer.According to the present invention, before decoding first sound channel, the huffman table that is used for first sound channel decoding unit 14 can be loaded into from storer 12, and when calculating the IMDCT of second sound channel, the huffman table that is used for second sound channel decoding unit 14 can be loaded into from storer 12.Decoding unit 14 can comprise the DSP that has huffman table of enough storages and store this movement on-chip memory of several these tables inadequately.
Comprise the DSP that supports direct memory exchange (DEM) as if decoding unit 14, the parallel storage loading when carrying out IMDCT calculating is useful especially so.In the case, DSP can carry out from memory access and load next required huffman table of next channel decoding according to this, and carries out the IMDCT calculating of current sound channel simultaneously.And, can carry out parallel computation subsequently and from memory fetches at audio frame subsequently.Specific, when audio-frequency information is resolved into a plurality of audio frame of a tonic train, decoding unit 14 can load the huffman table of first sound channel that is used for first audio frame before first sound channel of decoding first audio frame, load the huffman table of first sound channel that is used for second audio frame when when the IMDCT of second sound channel of calculating first audio frame, loading the huffman table of second sound channel that is used for first audio frame and IMDCT in second sound channel of calculating first audio frame.In this way, can carry out for each sound channel of audio frame of decoding subsequently and calculate simultaneously and from memory fetches.
Fig. 3 is graphic extension another process flow diagram according to the each side of audio decoder process of the present invention.As shown in FIG. 3, decoding unit 14 (for example) loads look-up tables being used for sound channel 1 (31) via direct memory access (DMA) (DMA) from storer 12, and (for example) uses the look-up table that loaded to sound channel 1 decode (32) then.Decoding unit 14 calculates the IMDCT (33) of sound channel 1 then, and loads different look-up tables to be used for sound channel 2 from storer 12 simultaneously, for example via direct memory exchange (DEM) (34).Then, decoding unit 14 can be decoded (35) and calculates the IMDCT (36) of sound channel 2 sound channel 2.
Decoding unit uses the IMDCT of described sound channel 1 and 2 to produce MS stereo information sound channel 1 and 2 (35) then.The MS stereo information comprises a left side and the right channel information that can be used to produce audio samples, and described audio samples can be used to define the drive signal that is used for a left side and right loudspeaker 16A and 16B again.As described above with respect to Figure 2, decoding unit 14 also can be carried out re-quantization to sound channel 1 and 2, for example before the corresponding IMDCT of each sound channel calculates.Under any circumstance, calculate the generation (37) that the MS stereo information takes place afterwards (33 and 36) at IMDCT.Then, decoding unit 14 can be carried out windowing and reproduce audio samples (38) at a left side and R channel.Driving circuit 15 can use described audio samples to define and drive loudspeaker 16A and the required voltage of 16B that is used for stereo output.
In addition, according to the present invention, can repeat to take place to calculate IMDCT simultaneously and DME loads next look-up table that will use in decoding at the sound channel in the successive audio frames of a tonic train 1 and 2.Fig. 4 comes this favourable technology of graphic extension in the context that an audio frame sequence is carried out Hofmann decoding.
As shown in Figure 4, decoding unit 14 loads the sound channel 1 (41) of huffman tables with first frame that is used for a tonic train from storer 12, for example via DMA.Decoding unit 14 uses the huffman table that has loaded to come decoded channels 1 (42) then.Decoding unit 14 calculates the IMDCT (44) of the sound channel 1 of first frame then, and loads the different sound channel 2 of huffman table to be used for first frame from storer 12 simultaneously, for example via DME (43).Then, decoding unit 14 can use the decode sound channel 2 (45) of first frame of the huffman table that is loaded in the IMDCT computing interval of the sound channel 1 of first frame.
Next, decoding unit calculates the IMDCT (47) of the sound channel 2 of first frame, and loads the sound channel 1 of different huffman tables with second frame that is used for described tonic train from storer 12 simultaneously, for example via DME (46).Decoding unit 14 can use the decode sound channel 1 (48) of second frame of the huffman table that is loaded in the IMDCT computing interval of the sound channel 2 of first frame then.
Next, decoding unit 14 calculates the IMDCT (50) of the sound channel 1 of second frame, and loads the sound channel 2 of different huffman tables with second frame that is used for described tonic train from storer 12 simultaneously, for example via DME (49).Then, decoding unit 14 can use the decode sound channel 2 (51) of second frame of the huffman table that is loaded in the IMDCT computing interval of the sound channel 1 of second frame.
Next, decoding unit 14 calculates the IMDCT (53) of the sound channel 2 of second frame, and loads the sound channel 1 of different huffman tables with the 3rd frame that is used for described tonic train from storer 12 simultaneously, for example via DME (49).This process can continuing through the MS encoded audio frame at any number of tonic train.Calculate by each follow-up IMDCT, can carrying out simultaneously, memory fetches reduces the stand-by period and quickens decode procedure with next required huffman table of loading.
This paper has set forth many embodiment.Yet, can make various modifications to the techniques described herein.For example, MS is stereo can be made up of two sound channels, maybe can refer to two sound channels in the multi-channel system (for example, multitrack surround sound system).In addition, can use the conversion of other type to be used for the MS stereo decoding, but not IMDCT.Equally, although this disclosure has been mentioned the huffman table that is used for huffman coding, can use the coding of other type according to the present invention.Huffman coding is a useful examples, because it causes lossless coding and decoding audio-frequency information.Other coding techniques especially needs from memory load searching coding techniques and also can have benefited from technology of the present invention with each sound channel of being used for audio frame subsequently.
The techniques described herein can be implemented in hardware, software, firmware or its arbitrary combination.If be implemented in the software, so described technology can relate to the computer-readable media that comprises procedure code, and described procedure code is when can carry out one or more in the technology described herein when video sequence being implemented carry out in the apparatus for encoding.Under described situation, computer-readable media can comprise random-access memory (ram), for example Synchronous Dynamic Random Access Memory (SDRAM), ROM (read-only memory) (ROM), nonvolatile RAM (NVRAM), EEPROM (Electrically Erasable Programmable Read Only Memo) (EEPROM), FLASH (quickflashing) storer, and similar storer.
Described procedure code can form of computer readable instructions be stored on the storer.Under described situation, processor (for example DSP) can be carried out the instruction that is stored in the storer, so that carry out one or more described audio decoder technology.In some cases, described technology can come the DSP of speech coding process to carry out by calling various nextport hardware component NextPorts.In other situation, described herein unit can be embodied as microprocessor, one or more application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGA) or some other hardware-combination of software.
Described and other embodiment is in the scope of claims of enclosing.

Claims (26)

1, a kind of device, it comprises:
Storer, it is used to store encoded audio-frequency information; And
Decoder element, it is used to the encoded information of decoding, wherein said decoder element can operate with:
Decode first sound channel of described audio-frequency information;
The correction inverse discrete cosine transform (IMDCT) of calculating described first sound channel before side in generation (MS) stereo information;
Decode second sound channel of described audio-frequency information;
Before producing described MS stereo information, calculate the IMDCT of described second sound channel; And
Use the described IMDCT of described first and second sound channels to produce described MS stereo information.
2, device as claimed in claim 1, wherein said decoder element can operate with:
Described first sound channel to described audio-frequency information before the described IMDCT that calculates described first sound channel is carried out re-quantization; And
Described second sound channel to described audio-frequency information before the described IMDCT that calculates described second sound channel is carried out re-quantization.
3, device as claimed in claim 1, it further comprises a left side and right boombox, wherein said MS stereo information comprises a left side and right channel information, and described decoder element can be operated a described left side and right channel information are carried out the audio samples that windowing and reproduction are used for a described left side and right boombox.
4, device as claimed in claim 1, described first sound channel of wherein decoding comprises described first sound channel of Hofmann decoding, and described second sound channel of wherein decoding comprises described second sound channel of Hofmann decoding.
5, device as claimed in claim 4, wherein said decoding unit can be operated the huffman table that is used for described first sound channel with loading before described first sound channel of decoding, and loads the huffman table that is used for described second sound channel when calculating the described IMDCT of described first sound channel.
6, device as claimed in claim 1, wherein said decoding unit can be operated described first and second sound channels with a plurality of audio frames of the tonic train of decoding.
7, device as claimed in claim 6, wherein said decoding unit can be operated to carry out Hofmann decoding, wherein said decoding unit can be operated to load the huffman table of described first sound channel that is used for described first audio frame before described first sound channel of decoding first audio frame, load the huffman table of first sound channel that is used for second audio frame when when the described IMDCT of described first sound channel of calculating described first audio frame, loading the huffman table of described second sound channel that is used for described first audio frame and described IMDCT in described second sound channel of calculating described first audio frame.
8, device as claimed in claim 1, wherein said decoding unit comprise the digital signal processor DSP of supporting direct memory exchange (DEM).
9, device as claimed in claim 1, wherein said device comprise at least one in following: digital music player, radio communication device, PDA(Personal Digital Assistant), laptop computer, desk-top computer, digital camera, digital video recording device, radio telephone and direct and two-way communicator.
10, the method for side (MS) stereo audio information in a kind of decoding, described method comprises:
Decode first sound channel of described audio-frequency information;
Before producing the MS stereo information, calculate the correction inverse discrete cosine transform (IMDCT) of described first sound channel;
Decode second sound channel of described audio-frequency information;
Before producing described MS stereo information, calculate the IMDCT of described second sound channel; And
Use the described IMDCT of described first and second sound channels to produce described MS stereo information.
11, method as claimed in claim 10, it further comprises:
Described first sound channel to described audio-frequency information before the described IMDCT that calculates described first sound channel is carried out re-quantization; And
Described second sound channel to described audio-frequency information before the described IMDCT that calculates described second sound channel is carried out re-quantization.
12, method as claimed in claim 10, wherein said MS stereo information comprises a left side and right channel information, described method further comprises carries out the audio samples that windowing and reproduction are used for a left side and right boombox to a described left side and right channel information.
13, method as claimed in claim 10, described first sound channel of wherein decoding comprise that described first sound channel of Hofmann decoding and described second sound channel of wherein decoding comprise described second sound channel of Hofmann decoding.
14, method as claimed in claim 13, it loads the huffman table that is used for described first sound channel before further being included in described first sound channel of decoding, and loads the huffman table that is used for described second sound channel when calculating the described IMDCT of described first sound channel.
15, method as claimed in claim 10, it further comprises described first and second sound channels of a plurality of audio frames of the tonic train of decoding.
16, method as claimed in claim 15, described first and second sound channels of wherein decoding comprise described first and second sound channels of Hofmann decoding, wherein said decoding unit loaded the huffman table of described first sound channel that is used for first audio frame before described first sound channel of decoding, when the described IMDCT of described first sound channel of calculating described first audio frame, load the huffman table of described second sound channel that is used for described first audio frame, and the huffman table that when the described IMDCT of described second sound channel of calculating described first audio frame, loads first sound channel that is used for second audio frame.
17, a kind of computer-readable media, it is included in the executable instruction that realizes following function when carrying out in the stereosonic device of side in the support (MS):
First sound channel of decoded audio information;
Before producing the MS stereo information, calculate the correction inverse discrete cosine transform (IMDCT) of described first sound channel;
Decode described second sound channel of described audio-frequency information;
Before producing described MS stereo information, calculate the IMDCT of described second sound channel; And
Use the described IMDCT of described first and second sound channels to produce the MS stereo information.
18, computer-readable media as claimed in claim 17, it further comprises the instruction that realizes following function:
Described first sound channel to described audio-frequency information before the described IMDCT that calculates described first sound channel is carried out re-quantization; And
Described second sound channel to described audio-frequency information before the described IMDCT that calculates described second sound channel is carried out re-quantization.
19, computer-readable media as claimed in claim 17, wherein said MS stereo information comprises a left side and right channel information, and wherein said instruction is carried out the audio samples that windowing and reproduction are used for a left side and right boombox to a described left side and right channel information.
20, computer-readable media as claimed in claim 17, wherein said instruction use decode described first sound channel and wherein said instruction of Hofmann decoding to use Hofmann decoding described second sound channel of decoding.
21, computer-readable media as claimed in claim 21, wherein said instruction loaded the huffman table that is used for described first sound channel before described first sound channel of decoding, and loaded the huffman table that is used for described second sound channel when calculating the described IMDCT of described first sound channel.
22, decode described first and second sound channels of a plurality of audio frames of a tonic train of computer-readable media as claimed in claim 17, wherein said instruction.
23, computer-readable media as claimed in claim 22, Hofmann decoding is used in wherein said instruction, wherein said instruction loaded the huffman table of described first sound channel that is used for described first audio frame before described first sound channel of decoding first audio frame, when the described IMDCT of described first sound channel of calculating described first audio frame, load the huffman table of described second sound channel that is used for described first audio frame, and when the described IMDCT of described second sound channel of calculating described first audio frame, load the huffman table of first sound channel that is used for second audio frame.
24, a kind of decoder element that is used for audio decoding apparatus, wherein said decoder element can operate with
First sound channel of decoded audio information;
The conversion of calculating described first sound channel before side in generation (MS) stereo information;
Decode described second sound channel of described audio-frequency information;
Before producing described MS stereo information, calculate the conversion of described second sound channel; And
Use the described conversion of described first and second sound channels to produce described MS stereo information.
25, decoder element as claimed in claim 24, the described conversion of wherein said first and second sound channels comprise revises inverse discrete cosine transform (IMDCT).
26, decoder element as claimed in claim 24, wherein said decoder element can be operated the table that is used for the described decoding of described first sound channel with loading before described first sound channel of decoding, and loads the table that is used for described second sound channel when calculating the described conversion of described first sound channel.
CNA2007800070939A 2006-03-02 2007-03-02 Audio decoding techniques for mid-side stereo Pending CN101395660A (en)

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